The W3C Reference Library is a general code base that can be used to
build clients and servers.  It contains code for accessing HTTP, FTP,
Gopher, News, WAIS, Telnet servers, and the local file system.
Furthermore it provides modules for parsing, managing and presenting
hypertext objects to the user and a wide spectra of generic programming
utilities.  The Library is the basis for many World-Wide Web
applications and all the W3C software is build on top of it.  The
Library is a required part of all other W3C applications in this
distribution.

Homepage:
https://www.w3.org/Library/
